In recent years, more and more retail establishments have employed self-service operations, in which customers utilize shopping carts and move through the establishment to collect the items which they wish to purchase. The selected articles are then transported to checkout counters where employees of the establishment ascertain the price of each selected item, often by use of a scanner at the checkout counter which reads a bar code printed on the item, and total the amount due, after which the employee receives payment from the customer in the form of cash, check or a credit or debit card to complete the transaction. While the use of self-service operations and the automation of price reading and machine entry by the use of scanners have greatly increased efficiency and reduced costs in retail establishments, a substantial number of clerks at the checkout counters are still required, and lines of customers waiting at the checkout counters to complete their transactions are still commonplace. A system which would reduce the number of clerks necessary, and which would facilitate the movement of customers through the checkout operations would therefore further enhance the efficiency of retail establishments using self-service operations.